>Biology is non-toxic. Biology is efficient. Biology is beautiful. Biology is technology. I have a huge problem, with especially the first two. Biology can be very toxic. Cobra snake venom is a product of biology. Cancer is a product of biology. Both can have horrific consequences for humans. Biology is not necessarily efficient. Take a look at pregnancy and birth and infancy. Before modern medicine and birth control…
There are plenty of weird things as well. Why can't humans synthesise vitamin C? My cat can; in fact, most animals can. But not humans and most other primates: we lost this ability. This is probably because at the time we didn't really need it as we got enough from dietary sources, but dropping it just because you don't need it right now is of course a bit silly and short-sighted, but nature doesn't have any foresight of course. This is the sort of thing why species go extinct.
Another well known "design flaw" is the blind spot in our eyes, which is there for no real reason in particular other than what we might call "legacy reasons" in programming terms.